Method of making articles



Patented Aug. 23, 1932 UNITED STATES GAMILLE nnnyr'us, or nnw ironx, n. Y.. A

METHOD on MAKING nn'rrcnns No Drawing.

This invention relates to making articles of hollow shape from plastic compositions containing derivatives of cellulose.

An object of my invention is to prepare articles of hollow shape from thermoplastic compositions containing derivatives of cellulose. Other objects of my invention will appear from the following detailed description. The making of hollow articles from plastic 1 compositions containing organic derivatives of cellulose in an economical manner has presented serious difliculties. If attempts are made to blow such hollow in molds by air or steam that is introduced under pressure, satis- 7 1'5 factory results are not obtained.

I have found that hollow articles may be made by placing a preformed closed hollow article made of a thermoplastic composition containing a derivative of cellulose and of simple construction within a mold of desired 301 tions of the temperature, there is provided a sort of automatic control whereby the pressure of the air or gas varies with the degree of softness of the plastic material. In this manner, the danger of having too great an air pressure when the plastic material is not soft enough to yield to this pressure is avoided.

In accordance with my invention I prepare hollow articles made from thermoplastic compositions containing a derivative of cellulose and a plastifier by placing a hollow but entirely closed article within a mold of desired shape and having any desired ornamental surface and then heating. Theheating causes the air or other gas within the hollow article to expand and also causes the thermoplastic Application filed October 4, 1939. Serial No.-397,453.

material to soften and the softened material is forced'against the walls of-thermold,iwhereupon anarticle is formed conforming exactly to the shape and interior surface of the mold.

suitable thermoplastic composition 5 containing a derivative of cellulose may be employed. I prefer to.use-organioderivatives. of cellulose such as organic esters of cellulose or cellulose 'ethers. Examples of organic esters ofIcellulose'arecellulose acetate, (11117 lose formate, e los pr pioh tea d cellulose butyrate 'while'examples of cellulose others are t yl c lulo e, methyl oel ul eeehs f h nzyloel ee a The th m p ti compositio oont ihe' be: sides. h d r va s of lul se e-su able 1astifi r- Example of such. pla ifi re or. soft ning age re d u yl et die hyl... tartrate, triacetin, diethyl phtha-lat'e, tripheg nyl pho pha cl ph nylol p pan etc- T as plastic comp o ion h ld prefera ly contain a comp ra ively l rge p opo on of. pl'e i-' fier so hat th mp t on is oemp rotive y soft whereby upon heatingit readilylyields to the ressur ofthe gas .e ntoi e with th hollow article- Th p astic c mposition. may contain pigments, dyes or other efi'ect mat rial c mmonly empl y d n suoh positions J l j. Ase star i g m te ial, lowhrtieles made of therm p as c mater al ereheed- I pref r o e p oy hol ow. art oles hat may e r a i y, a d, heaply m de he shape 7 f r such ar i l s should pr f rably oughly e pon l that of-the desir d fi al product. Thus if dolls or other'articles of elongated shape are to be ;made,jI prefer to empl y u y d r e pr mayvhereae for. articles simulating the shape offruit or vegetables' such as applies, oranges or pumpkins, 5

I prefer'to use spheres or ballsas the startmma e i l- Q K The tubes .or cylinders employed as the starting material may be formed byextrusion through dies, or they may be formed byjoin 9 ing together two sheets that have been curved to correspond to semi-cylinders. Obviously the ends of the tubes or cylinders are sealed in appropriate manner in order to entirely confine the atmosphere within them. 7

The finished article need not be an entirely enclosed article, but the enclosed article taken from the mold may be cut into desired shape.

It willbe seen that by my process hollow articles of thermoplastic compositions containing derivatives of cellulose may be made economically andfexpeditiously. Articles of any desired shapemay be made in this man ner and designs in relief or intaglio may be imparted to the surface thereof conforming to the design on the mold.

As an example, it may be pointed out that 3. Method of making articles comprising inserting a closed hollow article made of a thermoplastic composition containing cellulose acetate within a closed mold and then raising the temperature, whereby the thermoplastic composition softens and the gas confined within the hollow article expands and forces the same against thewalls of the mold.

In testimony whereof, I have hereunto subscribed my name.

" 7 CAMILLE DREYFUS.

articles simulating the appearances of fruits I V or vegetables such as pumpkinsyo'ranges or the like to be used asornaments for decoratingChristmas trees may be readily'made by this invention. .To do this, sheets of a ther moplastic material containing cellulose acetate and a relatively large proportion of a suitable plastifien such as dibutyl tartrate or triacetin; are shaped by pressing in a suitable press into the form of hemispheres,

and twohemispheres are joined by cement in'gto form aclosed sphere that is air-tight This sphere is placed in a mold having the shape of the desired fruit and the mold is heated. The elevated. temperature causes.

the air confined within the sphereto expand: V

and the thermoplastic materi l composing the walls thereof to soften. The softened thermoplastic material is" forced by the xpanding air onto the walls of the mold. The mold is then cooled and opened, and the ar tide is removed.

It is tobe understood that the'foregoing.

. detai ed description is givenmerely by way thegas confined-within thehollow article expands and forces the same; against the. wallsof the mold.-

2. Method of making articles comprising inserting a closed hollow articlemade of a thermoplastic composition containing-an organic:- derivative vof cellulose within a closed mold and then raising the-temperature, wherebythe thermoplastic composition I softens and the gas confined withinv the hollow article expands and forces the same against the walls of themold. 

